AUTHOR=Parra-Flores Julio , Rodriguez Alejandra , Riffo Francisca , Arvizu-Medrano Sofía M. , Arias-Rios E. Verónica , Aguirre Juan 

TITLE=Investigation on the Factors Affecting Cronobacter sakazakii Contamination Levels in Reconstituted Powdered Infant Formula

JOURNAL=Frontiers in Pediatrics

VOLUME=3

YEAR=2015

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2015.00072

DOI=10.3389/fped.2015.00072

ISSN=2296-2360

ABSTRACT=<sec id="ST1"><title>Introduction</title><p>Certain strains of <italic>Cronobacter sakazakii</italic> can cause serious invasive infections in children, mainly those &lt;2 months old and fed with powdered infant formula (PIF). The infectious dose of <italic>C. sakazakii</italic> is unknown but evidence suggests that it is approximately 1000 colony forming units (CFU). PIF is currently considered safe if its end-product <italic>C. sakazakii</italic> level is &lt;1 CFU/g. In this study, we determined the lag time, generation time (GT), and growth rate of five pooled <italic>C. sakazakii</italic> isolates to evaluate the factors affecting contamination levels in reconstituted PIF.</p></sec><sec id="ST2"><title>Methods</title><p>1.71 log CFU/ml of <italic>C. sakazakii</italic> were inoculated into 100 and 3000 ml of reconstituted PIF and incubated at 22 and 35°C. Growth was evaluated over a 24-h period. ComBase was used for modeling.</p></sec><sec id="ST3"><title>Results</title><p>In 3000 ml, the growth rate was 0.45 ± 0.02 log CFU/h with a lag phase of 3 ± 0.05 h and GT of 0.67 h at 22°C, while the growth rate was 0.73 ± 0.01 log CFU/h with a lag phase of 0.45 ± 0.03 h and GT of 0.41 h at 35° C.</p></sec><sec id="ST4"><title>Conclusion</title><p><italic>Cronobacter sakazakii</italic> grows rapidly in reconstituted PIF, especially at 35° C.</p></sec>